A player's role in the module as written is basically an audience member, passively listening to creepy and gross descriptions until the GM tells them they lost.
The only reason I gave this 2 stars is because some of the atmosphere and ideas are cool enough that a GM with better design chops can pull them out and use them elsehwere, or fix this broken module.
Great opening atmosphere is tarnished by some weirdly silly and completely unnecessarily gross stuff. Needs to decide whether it's atmospheric gothic horror where the terror is in what you don't see, gross-out body horror trading on shock value, or whimsical 4th-wall-breaking silliness where you can play real world songs on an organ for in-game effects. The good ideas are incredibly good, the bad ideas are really bad. Also the adventure itself is very weak, with an unsatisfying "meant-to-lose" ending that you need to hack significantly if you aren't running it as a one-shot with players that don't mind "gotcha" moments and dying horribly. Crucially, there are basically no meaningful decisions for the players to make. It's basically a tour of a death cult's house before everything dies. The only things the players can do is make things worse.
If you're looking for imagination fuel for an ongoing campaign, this has some awesome ideas. If you're looking for a fatalistic one-shot that trades on its cult reputation, you could maybe run this as is just to say you did it. You'll get some cool moments, but even a few small changes would fix its significant flaws and preserve the good stuff. I had to severely rewrite most of the module when running it and it turned out great, but any mediocre adventure can turn out great when you heavily rewrite it.
As is, the module has cool scenery but is terrible as a game. The way to win is easy, "don't play". The way to survive is also easy "just leave". The way to survive if you don't do either is just "don't touch anything, don't interact with anything, just let the GM read the description then go to the next room". You miss out on a little treasure this way but as the module's own NPC says, the treasure isn't worth it compared to the risks and curses. It still amazes me how many module designers fall into these amateur traps of creating environments that don't want to be explored and punish the players for trying to... Play.
All that said, you WILL be supporting Zak S. if you buy this, and that guy is a monster. There are a lot, lot, lot of other great adventures out there written by people who aren't monsters. Buy those instead. I wrote this review to honestly praise this cool-but-overrated module's good sides so I could point out it's not so special you need to suspend your conscience in order to buy it. You don't, not at all. There are no shortage of great creators with spooky ideas out there. Support them instead.